LoRa Mesh

The LoRa Mesh is implemented using OpenThread.

To understand the OpenThread terms and overall functionality, these guides are highly recommended:

• What is Thread?
• Node Roles and Types
• IPv6 Addressing (especially, RLOC unicast address)

Important, all the OpenThread CLI commands are accessible using LoRa.cli("command"), the complete list of commands is here. Please note some commands, can't execute, as some functionalities are not implemented (ex: Commissioning Role, Joiner Role, DNS).

This example shows how to:

• enable LoRa-Mesh network
• find neighbors (parent, children, other router direct connections)
• send PING to neighbors
• open UDP socket for:
  • listening incoming UDP packets and answering back (ACK)
  • sending packets to all neighbors
• toggle LED as packet/ping is received.

Lora Mesh example

• Source: https://github.com/pycom/pycom-libraries/blob/master/lib/lora_mesh/main.py
• Loramesh micropython library is available at https://github.com/pycom/pycom-libraries/blob/master/lib/lora_mesh/loramesh.py.

from network import LoRa
import socket
import time
import utime
import ubinascii
import pycom
import machine

from loramesh import Loramesh

lora = LoRa(mode=LoRa.LORA, region=LoRa.EU868, bandwidth=LoRa.BW_125KHZ, sf=7)
MAC = str(ubinascii.hexlify(lora.mac()))[2:-1]
print("LoRa MAC: %s"%MAC)

mesh = Loramesh(lora)

# waiting until it connected to Mesh network and
# it has some valid neighbors
while True:
    mesh.led_state()
    print("%d: State %s, single %s"%(time.time(), mesh.cli('state'), mesh.cli('singleton')))
    time.sleep(2)
    if not mesh.is_connected():
        continue

    neigbors = mesh.neighbors_ip()
    if len(neigbors) == 0:
        print('No neighbor')
        continue

    print('Neighbors found: %s'%neigbors)
    break

# create UDP socket
s = socket.socket(socket.AF_LORA, socket.SOCK_RAW)
myport = 1234
s.bind(myport)
pack_num = 1
msg = "Hello World! MAC: " + MAC + ", pack: "
ip = mesh.ip()

while True:
    mesh.led_state()
    print("%d: State %s, single %s, IP %s"%(time.time(), mesh.cli('state'), mesh.cli('singleton'), mesh.ip()))

    # check if topology changes, maybe RLOC IPv6 changed
    new_ip = mesh.ip()
    if ip != new_ip:
        print("IP changed from: %s to %s"%(ip, new_ip))
        ip = new_ip

    # listen for incomming packets
    rcv_data, rcv_addr = s.recvfrom(128)
    if len(rcv_data)>0:
        rcv_ip = rcv_addr[0]
        rcv_port = rcv_addr[1]
        print('Incomming %d bytes from %s (port %d)'%(len(rcv_data), rcv_ip, rcv_port))
        print(rcv_data)
        # could send some ACK pack:
        if rcv_data.startswith("Hello"):
            try:
                s.sendto('ACK ' + MAC + ' ' + str(rcv_data)[2:-1], (rcv_ip, rcv_port))
            except Exception:
                pass
        mesh.blink(7, .3)
        continue

    # update neighbors list
    neigbors = mesh.neighbors_ip()
    print("%d Neighbors %s"%(len(neigbors), neigbors))

    # send PING and UDP packets to all neighbors
    for neighbor in neigbors:
        if mesh.ping(neighbor) > 0:
            print('Ping OK from neighbor %s'%neighbor)
            mesh.blink(10, .1)
        else:
            print('Ping not received from neighbor %s'%neighbor)

        time.sleep(10)

        pack_num = pack_num + 1
        try:
            s.sendto(msg + str(pack_num), (neighbor, myport))
            print('Sent message to %s'%(neighbor))
        except Exception:
            pass
        time.sleep(20 + machine.rng()%20)

    # random sleep time
    time.sleep(30 + machine.rng()%30)